So I just discovered this thing here
It lets you play the Pokémon Card Game online.
It's surprisingly fun, though quite laggy/crashy during peak hours. Best time to play seems to be around 8:00AM (which is based on my timezone, EST, re-calculate as-applicable for your own timezones.)
Quick tip to anyone who tries it out: Play through the Single Player Gold League first. It's against NPC opponents (who are pretty easy) and forces you to use decks themed around the Gen V starters, but your card options are pretty limited at first anyways. Beating all of the early NPCs in the Gold League with the same deck awards you a copy of that deck, which opens up some deck-building possibilities, especially if you go through and do it three times, once with each basic deck. (The Basic Blue deck, which is based around Oshawott, Tympole, Feebas, Buneary, and Lapras seems to be easiest for beginners to win with, especially because its weaknesses take the longest of the three basic decks to show up in the league.)
My screen name there is Spryte4 in case anyone wants to have a look.